1. Field of the Invention
The present invention relates to capacitive discharge ignition systems in general and, more particularly, to a capacitive discharge ignition system with a single capacitive discharge ignition module including a plurality of charge storage capacitor devices provided to power a corresponding plurality of sets of ignition outputs.
2. Description of the Prior Art
Conventional ignition systems for internal combustion engines (ICE) have a battery, an ignition coil, a condenser (capacitor), breaker points and a distributor. These systems are known to have a number of disadvantages related to durability and performance. For example, in a typical ignition system, the voltage available to make a spark is at a maximum at idling speeds and decreases as engine speed (or ignition frequency) increases. It would be preferred to have a higher voltage available for the spark at higher firing frequencies. In the case of typical multi-cylinder engines, a high voltage distributor, made of a rotor and a distributor cap, directs the energy to the appropriate spark plug according to the engine crankshaft position through auxiliary air gaps.
The advent of reliable semiconductor device introduced technology which led to the gradual elimination of performance limitation and maintenance problems associated with the mechanical breaker. Transistor-assisted-contact systems (TAC) were introduced where a transistor device relieves the mechanical breaker points of the burden of carrying high current. More recently, mechanical breaker points have been entirely replaced by opto-electronic or inductive sensors coupled to electronic timing and driver circuitry that directly control the coil primary winding current (Transistor Coil Ignition system-TCI). Recently efforts have also been made to eliminate the conventional mechanical rotor system for high voltage ignition pulse distribution, mainly in using multiple coils (one coil per spark plug) or coils with multiple windings associated with high voltage diodes (several spark plugs connected to the same secondary coil winding, plug selection made by using energy polarization).
With further advances in solid state electronics, transistorized electronic ignition systems have become available, and automobile manufacturers now typically provide either inductive or capacitive discharge ignition systems with their products. An inductive discharge ignition system uses a transistor to cut off the current flowing in the primary winding of the ignition coil.
A capacitive discharge ignition (CDI) system typically uses a silicon controlled rectifier to discharge a previously charged capacitor through the primary winding of the ignition coil. As in the conventional ignition system, the voltage applied to the spark plug in an electronic ignition system typically decreases as engine speed increases. A limitation of existing CDI systems is the requirement of a minimum recharge time (typically 0.5 to 2 ms) that must be allowed to ensure that any subsequent discharging of the ignition delivers the full energy. Some of the known CDI systems are disclosed in the following U.S. Pat. Nos. each of which is incorporated herein by reference: 3,605,714; 3,884,207; 4,366,801; 4,369,758; 4,418,660; 4,441,479; 4,445,491; 4,455,989; 4,690,124; 4,739,185; 4,825,844; 5,163,411; 5,178,120; 5,315, 982; 5,510,952; 5,513,618; 5,654,868.
While known CDI systems, including but not limited to those cited above, have proven to be acceptable for various ICE ignition applications, such devices are nevertheless susceptible to improvements that may enhance their performance and reduce cost. With this in mind, a need exists to overcome these shortcomings of the CDI systems of the prior art and to develop improved CDI system that advances the art.